Hollow Face Illusions Videos:
These videos show a variety of hollow face illusions at work. As the camera operators move around the sculptures, the faces (sometimes just the eyes) turn to watch the viewer.
How it Works:
Hollow face illusions are exactly what their name implies. The artist sculpts, carves or in the case of paper or origami art, folds the material to form a “hollow” face. The human eye is trained to see a face as being convex (bulging towards the viewer), that it naturally mistakes a concave face (bulging away from the viewer) as being convex. Small sculptures can be rotated horizontally and vertically to create the impression that the head displayed is turning from side to side or up and down. For large sculptures, the viewer can move around the sculpture, marveling at the supposed manner in which the face turns to follow the viewer around the room.
Above: The face on the left is convex, and the face on the right is concave. From this angle, with the light coming from above, the illusion is easily broken.
Above: Because the light source is apparent, the illusion created by this Buddha hollow face illusion is strong. The contrasting colors between “raised” and “indented” surfaces adds to the illusion.
Above: This image of Einstein appears to protruding out of the background, but is it?
The theories used in hollow face illusions and by da Vinci for the “Mona Lisa” are similar, but not exactly the same. Instead of creating a hollow face for Mona, da Vinci used perspective, contrast, shadows and shape to create the illusion that the Mona Lisa’s eyes turn to follow the viewer around the room. Da Vinci created a sketch called Proportions of the Face, which he used as a base for the proportions of the Mona Lisa’s face. The proportions created by da Vinci are based on the same mathematical principles as hollow face illusions, and create a similar effect.
Above: Working stages of the Mona Lisa painting, showing how da Vinci incorporated his sketch, Proportions of the Face, into the final Mona Lisa masterpiece. The reason why Mona's eyes seem to follow you around the room is a combination of light and shadows in the piece and layers upon layer of paint that give the painting a slight 3-Dimensional effect.
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